Search results for "Pyrolysis"
showing 10 items of 170 documents
Mechanism of co-pyrolysis of coal-tar pitch with polyacrylonitrile
2003
Abstract Co-pyrolysis of coal-tar pitch with polyacrylonitrile (PAN) and PAN oxidized in air at 300 °C was studied as a possible way of manufacturing of carbonaceous materials enriched in nitrogen. The thermal behaviour of components and blends was evaluated by thermogravimetry and optical microscopy of solid residues. The transformation of nitrogen functional groups on co-treatment was monitored using elemental analysis, infrared spectroscopy and X-ray photoelectron spectroscopy. Oxidized polymer behaved as an inert during co-pyrolysis. In contrast, strong interactions of unoxidized PAN with pitch could be deduced from enhanced residue yield and extensive deterioration of the optical textu…
Solid-state pyrolysis of polyphenylene-metal complexes: A facile approach toward carbon nanoparticles
2007
Novel polyphenylene-metal complexes with discotic, linear, and dendritic geometries are synthesized by using a facile approach consisting of reactions between Co2(CO)8 and ethynyl functionalities in dichloromethane. Various carbon nanoparticles (CNPs), including graphitic carbon nanotubes (CNTs), graphitic carbon rods, and carbon-metal hybrid particles are obtained from the solid-state pyrolysis of these complexes. The ultimate structures of the CNPs are found to be dependant on the structure and composition of the starting compounds. Precursors containing graphenes always result in graphitic CNTs in high yield, whereas dendritic precursors give rodlike carbon materials. Alternatively, line…
Self-Assembled Zinc Oxide Quantum Dots Using Spray Pyrolysis Methodology
2011
Self-assembled ZnO quantum dots (QDs) have been obtained on different substrates by using the atmospheric spray pyrolysis methodology under well-defined growth conditions. The evolution of size and...
Ester-Ester Exchange Reactions of Aliphatic Polyesters
1979
Abstract The kinetics of ester-ester exchange reactions of poly(ethylene adipate) and poly(trimethylene adipate) at 312°C and in the absence of a solvent and catalysts has been reported previously. Independent investigations of the thermal degradation reactions of these polyesters under high vacuum have shown that pyrolysis already starts above 270°C. An ester-ester exchange mechanism via a reversible thermal degradation reaction is proposed.
Synthesis and properties of magnetic iron oxide/platinum nanocomposites
2015
Iron oxide/platinum nanocomposites have been synthesized by the extractive-pyrolytic method (EPM) involving gradual decomposition of iron capronate and n-trioctylammonium hexachloroplatinate initially produced by solvent extraction. The content of platinum in the composites was 1.2 wt%, 2.4 wt% and 4.8 wt%. Phase composition, morphology and magnetic properties of the produced materials were investigated. XRD analysis and magnetic measurements show that the magnetic phase (magnetite Fe3O4) dominates in a carrier sample produced by the pyrolysis of iron carboxylate, but hematite α-Fe2O3 exists there as an admixture. Referring to the TEM results, the produced composites contain ultra-disperse …
Properties of atomic layer deposited nanolaminates of zirconium and cobalt oxides
2018
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Considerations on factors affecting biochar densification behavior based on a multiparameter model
2021
The optimization of upscaled biochar pelleting is limited by lack of knowledge regarding the effects of process parameters. A multiparameter model, coupled to a single pellet press unit, was for the first time applied to biochar production to predict the upscaled biochar pelleting process behavior. The model permits to estimate in a time and cost-effective way how the die friction forces, quantified through the pellet exiting pressure, are affected by the key process parameters. It was observed that to achieve acceptably low exiting pressures (in the order of 100 MPa), it was critical to produce biochar at high temperatures (e.g. 600 °C). Addition of water as a binder is also beneficial, wh…
Preparation and characterization of activated carbon from date stones by physical activation with steam
2008
Abstract Activated carbons are produced from wastes of Algerian date stones by pyrolysis and physical activation in the presence of water vapor into a heated fixed-bed reactor. The effect of pyrolysis temperature and activation hold time on textural and chemical surface properties of raw date stones and carbon materials produced are studied. As expected, the percentage yield decreases with increase of activation temperature and hold time. The characterization of carbon materials is performed by scanning electron microscopy (SEM). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption (BET). Results show the presence of cellulose and hemicellulose in …
Experimental study of the pyrolysis of waste bitumen for oil production
2020
Abstract This work focuses on bitumen slow pyrolysis. Mass and energy yields of oil, solid and gas were obtained from pyrolysis experiments using a semi-batch reactor in a nitrogen atmosphere, under three non-isothermal conditions (maximum temperature: 450 °C, 500 °C and 550 °C). The effect of temperature on the product yields was discussed. The gas compositions were analysed using gas chromatography (GC) and the heating value of oil and solid residue was also measured. Using a thermo-gravimetric analyser, kinetic parameters were evaluated through Ozawa-Flynn-Wall (OFW) method. Results showed that oil yield is maximum at 500 °C (50%). Moreover, gas yield increased with increasing pyrolysis …
A Review of using spray pyrolysis through Sol-gel materials in the synthesis of cathode materials for lithium-ion batteries
2016
Over the years, new synthesis routes of the cathode electrochemical active material for lithium-ion batteries have improved remarkably to optimize their capacity and cycle life performance. This review study focused on the use of some techniques to synthesize the common cathode materials (LiCoO2, LiMn2O4, LiFePO4). The most common and simplest synthesis method was the mixing of powders in their solid-state form and heating them at relatively high temperatures over long periods. Other methods included the formation of sol-gel products that could be either heat-treated more or could be used directly by means of a spray pyrolysis method producing the desired active material. The spray pyrolysi…